This invention relates to photoelectric converters and to large-area solar cells having a compact form.
One known solar cell is made from a single-crystal plate of lithium niobiate whose opposite surfaces carry applied electrodes made from the same metal. In such a cell, the lithium niobiate crystal (active zone) is used as a converter of the energy of solar radiation photons falling on one of the electrodes into charge carriers which are stored with the aid of an electrical energy capacitor-type accumulator. It is known that the amount of charge carriers in the active zone (semiconductor plate), may be increased if the plate surface facing the radiation source is covered with a current-conducting film made of tin oxide; applied atop the film is a coating made of cadmium sulfide containing indium. The metal electrodes are provided on the cadmium-sulfide coating and on the opposite surface of the semiconductor plate. Thus, applied to the opposing surfaces of the plate are electrodes which have different electrochemical potentials which significantly add to the amount of the charge carriers dislodged by the photons of incident radiation. A disadvantage of this structure is that the rigid semiconductor plate does not permit manufacture of a compact solar cell having a low cost, large dimension of radiation-absorbent surface, and low weight.
Another known semiconductor device used for converting light energy into electrical energy has an active zone made of hydrogenated amorphous silicon with heterogeneous electrodes applied to the opposing surfaces and an absorbing coating is applied on the solar-radiation incident surface. Though such a device is more effective to convert the energy and is inexpensive to manufacture, it has the disadvantages typical of the above described solar cells. A solar cell made of hydrogenated amorphous silicon applied on a polyethyleneterephthalate flexible ribbon is known, which makes it possible to create flexible structures of the solar cell but does not reduce its cost.
Still another solar cell was developed which has an active zone made of semiconductor material which is coated on both sides with oxide layers provided with holes. On the side where the solar rays are incident, the holes are provided with metal contacts and the holes serve as the concentrators of radiation. The presence of holes increases the effectiveness of the energy conversion and attributes to lessening of the cell weight; however, the use of semiconductor material as the active zone material increases the cost of the solar cell and makes it impossible to create a large-area converter which, when in transit, has a compact form and small dimensions.